[PATCH ver 6] rs6000: Add builtins for IEEE 128-bit floating point values

[Kewen.Lin]

Hi Carl,

on 2023/6/20 02:54, Carl Love wrote:
> 
> Kewen, GCC maintainers:
> 
> Version 6, Fixed missing change log entry.  Changed builtin id names as
> requested.  Missed making the change on the last version.  Fixed
> comment in the three test cases.  Reran regression suite on Power 10,
> no regressions.
> 
> Version 5, Tested the patch on P9 BE per request.  Fixed up test case
> to get the correct expected values for BE and LE.  Fixed typos. 
> Updated the doc/extend.texi to clarify the vector arguments.  Changed
> test file names per request.  Moved builtin defs next to related
> definitions.  Renamed new mode_attr. Removed new mode_iterator, used
> existing iterator instead. Renamed mode_iterator VSEEQP_DI to V2DI_DI. 
> Fixed up overloaded definitions per request.
> 
> Version 4, added missing cases for new xxexpqp, xsxexpdp and xsxsigqp
> cases to rs6000_expand_builtin.  Merged the new define_insn definitions
> with the existing definitions.  Renamed the builtins by removing the
> __builtin_ prefix from the names.  Fixed the documentation for the
> builtins.  Updated the test files to check the desired instructions
> were generated.  Retested patch on Power 10 with no regressions.
> 
> Version 3, was able to get the overloaded version of scalar_insert_exp
> to work and the change to xsxexpqp_f128_<mode> define instruction to
> work with the suggestions from Kewen.  
> 
> Version 2, I have addressed the various comments from Kewen.  I had
> issues with adding an additional overloaded version of
> scalar_insert_exp with vector arguments.  The overload infrastructure
> didn't work with a mix of scalar and vector arguments.  I did rename
> the __builtin_insertf128_exp to __builtin_vsx_scalar_insert_exp_qp make
> it similar to the existing builtin.  I also wasn't able to get the
> suggested merge of xsxexpqp_f128_<mode> with xsxexpqp_<mode> to work so
> I left the two simpler definitiions.
> 
> The patch add three new builtins to extract the significand and
> exponent of an IEEE float 128-bit value where the builtin argument is a
> vector.  Additionally, a builtin to insert the exponent into an IEEE
> float 128-bit vector argument is added.  These builtins were requested
> since there is no clean and optimal way to transfer between a vector
> and a scalar IEEE 128 bit value.
> 
> The patch has been tested on Power 9 BE and Power 10 LE with no
> regressions.  Please let me know if the patch is acceptable or not. 
> Thanks.

OK for trunk with some nits fixed in changelog (sorry that I didn't catch
all of them in previous review, but I don't think you need to post
a new version).  Thanks!

> 
>                Carl
> 
> --------------------------------------------
> rs6000: Add builtins for IEEE 128-bit floating point values
> 
> Add support for the following builtins:
> 
>  __vector unsigned long long int scalar_extract_exp_to_vec (__ieee128);
>  __vector unsigned __int128 scalar_extract_sig_to_vec (__ieee128);
>  __ieee128 scalar_insert_exp (__vector unsigned __int128,
>  			      __vector unsigned long long);
> 
> The instructions used in the builtins operate on vector registers.  Thus
> the result must be moved to a scalar type.  There is no clean, performant
> way to do this.  The user code typically needs the result as a vector
> anyway.
> 
> gcc/
> 	* config/rs6000/rs6000-builtin.cc (rs6000_expand_builtin):
> 	Rename CCDE_FOR_xsxexpqp_tf to CODE_FOR_xsxexpqp_tf_di.
> 	Rename CODE_FOR_xsxexpqp_kf to CODE_FOR_xsxexpqp_kf_di.


Miss 
	"Rename CODE_FOR_xsxsigqp_tf to CODE_FOR_xsxsigqp_tf_ti."
	"Rename CODE_FOR_xsxsigqp_kf to CODE_FOR_xsxsigqp_kf_ti."
	"Rename CODE_FOR_xsiexpqp_tf to CODE_FOR_xsiexpqp_tf_di."
	"Rename CODE_FOR_xsiexpqp_kf to CODE_FOR_xsiexpqp_kf_di."

> 	(CODE_FOR_xsxexpqp_kf_v2di, CODE_FOR_xsxsigqp_kf_v1ti,
> 	CODE_FOR_xsiexpqp_kf_v2di): Add case statements.
> 	* config/rs6000/rs6000-buildin.def (__builtin_extractf128_exp,
> 	 __builtin_extractf128_sig, __builtin_insertf128_exp): Add new
> 	builtin definitions.

Should be with correct names:

	(__builtin_vsx_scalar_extract_exp_to_vec,
	__builtin_vsx_scalar_extract_sig_to_vec,
	__builtin_vsx_scalar_insert_exp_vqp):

> 	Rename xsxexpqp_kf, xsxsigqp_kf, xsiexpqp_kf to xsexpqp_kf_di,
> 	xsxsigqp_kf_ti, xsiexpqp_kf_di respectively.
> 	* config/rs6000/rs6000-c.cc (altivec_resolve_overloaded_builtin):
> 	Update case RS6000_OVLD_VEC_VSIE to handle MODE_VECTOR_INT for new
> 	overloaded instance. Update comments.
> 	* config/rs6000/rs6000-overload.def
> 	(__builtin_vec_scalar_insert_exp): Add new overload definition with
> 	vector arguments.
> 	(scalar_extract_exp_to_vec, scalar_extract_sig_to_vec): New
> 	overloaded definitions.
> 	* config/vsx.md (V2DI_DI): New mode iterator.
> 	(DI_to_TI): New mode attribute.
> 	Rename xsxexpqp_<mode> to sxexpqp_<IEEE128:mode>_<V2DI_DI:mode>.
> 	Rename xsxsigqp_<mode> to xsxsigqp_<IEEE128:mode>_<VEC_TI:mode>.
> 	Rename xsiexpqp_<mode> to xsiexpqp_<IEEE128:mode>_<V2DI_DI:mode>.
> 	* doc/extend.texi (__builtin_extractf128_exp,
> 	__builtin_extractf128_sig): Add documentation for new builtins.

Should be with correct names:

	(scalar_extract_exp_to_vec, scalar_extract_sig_to_vec):

BR,
Kewen